Demo: Fixed "Log" demo not initializing properly, leading to the first line not showing before a Clear. (#2318) [@bluescan]

imgui_demo.cpp

@@ -3397,6 +3397,12 @@ struct ExampleAppLog
     ImVector<int>       LineOffsets;        // Index to lines offset. We maintain this with AddLog() calls, allowing us to have a random access on lines
     bool                ScrollToBottom;
 
+    ExampleAppLog()
+    {
+        ScrollToBottom = false;
+        Clear();
+    }
+
     void    Clear()
     {
         Buf.clear();